A married couple are father-in-lawfathers-in-lawhalf-brothershalf-sistershusband and wifesister-in-lawsisters-in-lawspousestep-brothersstep-fatherstep-motherstep-sisters. Each is called the father-in-lawfathers-in-lawhalf-brothershalf-sistershusband and wifesister-in-lawsisters-in-lawspousestep-brothersstep-fatherstep-motherstep-sisters of the other. The words for relatives by marriage are the same as with your immediate family, but with -in-law added. So your spouse's father is your father-in-lawfathers-in-lawhalf-brothershalf-sistershusband and wifesister-in-lawsisters-in-lawspousestep-brothersstep-fatherstep-motherstep-sisters and their sister is your father-in-lawfathers-in-lawhalf-brothershalf-sistershusband and wifesister-in-lawsisters-in-lawspousestep-brothersstep-fatherstep-motherstep-sisters. The plural of these forms is father-in-lawfathers-in-lawhalf-brothershalf-sistershusband and wifesister-in-lawsisters-in-lawspousestep-brothersstep-fatherstep-motherstep-sisters and father-in-lawfathers-in-lawhalf-brothershalf-sistershusband and wifesister-in-lawsisters-in-lawspousestep-brothersstep-fatherstep-motherstep-sisters. Death and divorce mean that people remarry and have children with a different parent. This parent by marriage is called your father-in-lawfathers-in-lawhalf-brothershalf-sistershusband and wifesister-in-lawsisters-in-lawspousestep-brothersstep-fatherstep-motherstep-sisters or father-in-lawfathers-in-lawhalf-brothershalf-sistershusband and wifesister-in-lawsisters-in-lawspousestep-brothersstep-fatherstep-motherstep-sisters. Any children they may already have become your father-in-lawfathers-in-lawhalf-brothershalf-sistershusband and wifesister-in-lawsisters-in-lawspousestep-brothersstep-fatherstep-motherstep-sisters and father-in-lawfathers-in-lawhalf-brothershalf-sistershusband and wifesister-in-lawsisters-in-lawspousestep-brothersstep-fatherstep-motherstep-sisters. The children they go on to have with your actual mother or father are your father-in-lawfathers-in-lawhalf-brothershalf-sistershusband and wifesister-in-lawsisters-in-lawspousestep-brothersstep-fatherstep-motherstep-sisters or father-in-lawfathers-in-lawhalf-brothershalf-sistershusband and wifesister-in-lawsisters-in-lawspousestep-brothersstep-fatherstep-motherstep-sisters.